Original-clinicalRelationship between arrhythmogenesis and disease activity in cardiac sarcoidosis
Introduction
Sarcoidosis is a multisystem granulomatous disease of unknown etiology. Clinical manifestations and causes of death vary in different geographic regions.1, 2, 3 Cardiac involvement occurs in 20% to 27% of sarcoidosis patients in the United States and may occur in as many as 58% of patients in Japan.4, 5, 6 Manifestations of cardiac sarcoidosis include ventricular aneurysms, congestive heart failure, pericarditis, pericardial effusion, conduction abnormalities, and arrhythmias.7 Complete atrioventricular block (CAVB), ventricular arrhythmias, and congestive heart failure occur frequently and can be fatal. Ventricular tachycardia (VT) and CAVB are presumed to be the cause of sudden cardiac death in many patients with sarcoidosis. Thus, prevention and early treatment of these severe arrhythmic events are important for improving the prognosis.8 A better understanding of the underlying arrhythmogenic mechanism in cardiac sarcoidosis would be beneficial.
In cardiac sarcoidosis patients with left ventricular dysfunction, sustained VT occurs and frequently is inducible at electrophysiologic study. The mechanism of sustained VT in cardiac sarcoidosis is presumed to be reentry related to myocardial scar tissue.9 On the other hand, conduction abnormalities result from involvement of the basal intraventricular septum due to sarcoid granuloma or scar tissue.6, 10
Gallium-67 citrate (Ga) scintigraphy not only is a useful means for diagnosing cardiac sarcoidosis but also is useful in the assessment of disease activity of sarcoidosis.11, 12, 13, 14 However, few reports on the relationship between disease activity and arrhythmic events are available. Accordingly, we investigated the relationship between disease activity and occurrence of severe arrhythmic events in cardiac sarcoidosis and the effect of corticosteroid therapy on arrhythmia in the active cardiac sarcoidosis phase.
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Study population and diagnostic criteria
Between July 1995 and August 2005, 15 patients diagnosed with cardiac sarcoidosis underwent cardiac assessment in our institution, including 12-lead ECG, ultrasound cardiography, coronary angiography, and left ventriculography. Diagnostic criteria for cardiac sarcoidosis established by the Specific Diffuse Pulmonary Disease Research Group, Sarcoidosis Division of the Japanese Ministry of Health, Labor, and Welfare were used.15 The criteria include category 1—histologic confirmation of
Patient characteristics
A total of 15 patients (8 men and 7 women; mean age 56 ± 13 years) were evaluated (Table 1). Reasons for hospitalization in all patients were CAVB or sustained VT. Clinically documented arrhythmic events were CAVB (n = 10), VPCs, and sustained VT (n = 7). According to the diagnostic criteria, category 1 findings were found in 6 patients, with findings based on endomyocardial biopsy in five patients and findings based on postmortem examination in one patient (no. 14). Average age at onset of
Discussion
In this study, we investigated the relationship between disease activity and arrhythmic events in cardiac sarcoidosis, focusing on new-onset symptomatic arrhythmia and the effect of corticosteroid therapy.
Conclusion
In cardiac sarcoidosis patients, CAVB develops mainly in the active phase, and early treatment with a corticosteroid might improve the AV conduction disturbance. In contrast, sustained VT is not closely linked with disease activity and frequently develops in the advanced stage of disease.
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